This project focuses on long-term consequences of individual differences in physical, social, and affective functioning and the description of early interaction in diverse ecological contexts. In one longitudinal study, measures of behavioral synchrony in the home predicted differences in the security of infant-mother attachment as reported by the mothers. In a second project, we are studying infant-mother interaction and attachment in infants from upper-middle class Euro-Americans and low- class Central American families, developing culturally-sensitive criteria for evaluating normative social behavior and development. Regardless of social or ethnic background, mothers spent comparable amounts of time in discrete activities such as feeding, caring for, and playing with their infants. Comparable observations of mothers and infants in Costa Rica are designed to further explore the effects of culture and context on early interactions.